Addiction works as a non-linear system. The more a person induces the gratification-generating stimulus, the less gratifying it becomes as the brain learns to habituate its response to it. In trying to re-experience that stimulus at its original full impact, the person is driven to re-induce the stimulus. The decline in gratification keeps at a loosely direct proportion to the frequency that the stimulus is induced.

The evolutional value of the addiction mechanism is clear -- anything that drives a species to eat more and mate more increases that species replicative value. Those that only eat as much as they need aren't going to survive as well as those that keep eating as much as they can, regardless of whether they produce pleasure out of it or not. More directly, those that reproduce compulsively are going to spread their genes much more effectively than those that only do for as long as it provides them with pleasure.

addiction: a state or condition of existence characterized by habitually engaging in a highly specific and routine activity reiteratively and compulsively, irrespective of aversive or deadly consequences; the addiction is not to the activity, but to the object, substance, or person toward which the activity is directed. Seealso sexual addiction

The condition in which the need of oneself to perform a certain activity to satisfy a desire is great enough to cause the person to continue the behaviour.

An addiction is not necessarily harmful to one's health, nor is it necessarily a negative situation to be in. This is a key point that many drug warriors fail to recognise. The harmfulness of an addiction is determined not by its presense nor by the severity of it, but by the dangers of the behaviour to which one is addicted. Drug warriors sometimes state the possibility of addiction alone as a reason to abstain from drug use, when in reality one should be concerned with the direct firsthand dangers of taking the drug in question, in light of the fact that addiction could occur.

The severity of an addiction is determined by the strength of the desire to perform the activity. For instance, a user addicted to crack, running low on money, may eventually favour paying for a hit on the crack pipe over purchasing food, leading to starvation. Other addictions, such as to Cannabis, are never strong enough to force the user to make sacrifices to their health, other than those caused by the drug itself, which are minimal.

Addictions are not limited to drug use, however. Common addictions are to:

Addictions can become degrading to one's overall well-being for several reasons. It may become difficult for one to finance their habit. The crackhead example was illustrated earlier. Also, addictions can be time-consuming. This can make experiencing pleasure through other means more difficult. In addition, addictions tend to piss people off, especially in respect to drug use. Today's society has little understanding of drugs, drug users, and drug culture. Finally, the activity to which one is addicted can be harmful directly to the person's health.

Addiction is a relatively new E2 statistic invented by kthejoker which is calculated by dividing a user's devotion by the number of days since they they joined Everything2. Because devotion is merit multiplied by the number of writeups a user has written, addiction measures both the quality of a users writeups, and how fast they node. It's a pretty fun metric because it is constantly dropping, and you have to node like a maniac to make it go up!

As of this writing, here are the top 25 users (not including reincarnated users), as measured by their "addiction" to E2: